Diabetes

 Diabetes is a condition where not enough insulin is made. This means that blood sugar levels can go up and down, with various effects on the body.

Risks if you have diabetes, or have it but not been diagnosed.

• You are twice as likely to have a heart attack or stroke than someone without diabetes.
• High levels of glucose damage the eyes, kidneys and nerves.
• Women with breast cancer and diabetes are more likely to have problems with tiredness, sleep disturbance and sexual problems compared to those who don't.

There are two types of diabetes.

Type 1 is an auto-immune  disease. Your immune system attacks your pancreas, and stops it producing insulin. It has nothing to do with weight or lifestyle, and you will need insulin administered from day 1.

A small minority of people have rarer forms of diabetes, including maturity onset diabetes of the young (MODY) and latent autoimmune diabetes in adults (LADA).

It can't be cured, but meticulous monitoring and insulin treatment can greatly reduce the risk of complications.

Type 1 - Monogenetic diabetes. People with this condition produce some insulin, but less than healthy people. They often present with similar problems as those with type 1 diabetes, such as constant thirst and subsequent need to urinate, blurred vision and weight loss, which is why the two conditions are often confused. But since they produce some small amounts of insulin, it could be possible to control their condition with 'dietary tweaks' or daily tablets that stimulate the body to produce more insulin. (Type 1 patients can't take these tablets as they are unable to produce insulin.) 

Until now doctors have struggled to diagnose this condition, but  now increased training and testing is finding more patients. If patients constantly struggle with varying blood sugar levels, it might be due to monogenic diabetes rather than simple type 1.

Monogenic diabetes is caused by a genetic fault that leads to the pancreas producing less insulin. There are numerous sub-types of this condition, linked to problems with different genes and it tends to run in families. The usual HbA1c blood test only shows that someone has the diabetes, not which type. If a parent is diagnosed with type 1 diabetes, it may be worth testing parent and child(ren) for monogenic diabetes.

Type 2 is almost all about lifestyle. It is mostly about your body's ability to process insulin.

Risk of developing diabetes. Obesity is the biggest risk factor, accounting for 80 to 85% of the risk of developing diabetes. Those of South Asian or Afro-Caribbean origin also have an increased risk. Some women  develop diabetes during pregnancy; while their blood glucose usually settles after delivery, they remain at higher risk of developing diabetes type 2 in later life.

Until a few years ago it was considered a chronic, progressive disease. Then a 2016 study demonstrated that after eight weeks on a very low calorie diet (VLCD) people lost substantial amounts of weight, and if this was maintained for at least six months, more than two in five had glucose levels in the normal range. It is thought that the weight loss removed excess fat from the pancreas, allowing if to produce insulin more efficiently, thus controlling blood glucose effectively. This needs to be overseen in a medical setting, but while Type 2 diabetes cannot be cured, it now seems possible to stay in remission. NHS England has agreed to start providing access to VLCDs on the NHS.

The basis for the low carb diet is the increased understanding that starchy carbs (e.g. bread, potatoes or breakfast cereals) digest down to a surprisingly large amount of sugar.

Not everyone can achieve remission with diet but there are signs that another treatment can help. The surgical procedure Revita (endoscopic duodenal mucosal resurfacing) has been shown to be beneficial but is not currently available on the NHS. 

Sources: Feature Diabetes: the other health crisis by Dr Sarah Jarvis, in Good Housekeeping, July 2020 and article in Daily Mail by Ethan Ennals on 6th Nov. 2021.

Covid-19 Infection and Transmission in Children

 In the early days of Covid-19 it was thought that children might be more susceptible to catching the virus and more likely to spread it, as is the case with flu. However, the evidence from many countries is that it appears that this is not the case.

• Children have a very low risk of becoming ill if they catch Covid-19.
• A study of 55,000+ patients found that just 0.8% were under the age of 19.
• At 31 July 2020, those admitted to critical care units in England, Wale and Northern Ireland were 60 or older. More than three-quarters (75%) were over 50, and fewer than 10% were younger than 40.
• Children often have a 'milder disease than adults'. Although cases of an inflammatory syndrome have been reported, this is extremely rare.
• August 2020. There is some evidence that infected children present with gastric symptoms such as diarrhoea, vomiting and abdominal cramps. A US study of 992 children revealed 68 had virus antibodies. Of the 68, around a third (21) had fever, and nearly a quarter (13) had gastric symptoms. 

This finding is replicated across the globe.

• China: none of the infections in family groups were likely to have been introduced by children.
• French Alps: children testing positive did not pass it on to anyone of the more than 100 people they had had contact with.
• Community studies in Iceland, South Korea, Italy (which tested 70% of its population) and the Netherlands all found evidence that children were less likely to have (or have had) the virus than adults.

One theory is that as children are still developing physically, their lungs have fewer ACE2 receptors (which the virus uses to infect people) than adults.

On the issue of school opening, it is thought that any spread is more likely among the staff and among parents at the school gate.

Source. Article in New Scientist, July 2020 plus other later news items.

Keep Make-up Brushes Clean

Make-up brushes should be cleaned regularly to avoid giving you blemishes.

Wash brushes in warm, soapy water into which you mix a little coconut oil. It will help break down make-up residue to keep them clean, and ensure the bristles stay soft.

Source: Sunayah Arshad in Good Housekeeping, May 2019

The Health Difference Between Women and Men

Health outcomes are very different between the sexes. It has been known for some time that women generally outlive men, and are less susceptible to some illnesses and more susceptible to others. 

(This article concentrates on the typical XX (female) and XY (male), and ignores the sex chromosome abnormalities of loss, damage or addition of one or both sex chromosomes, which cause a number of developmental syndromes.)

In humans, sex is largely determined by chromosomes that carry tightly coiled DNA that carry our genes. The cells of most women possess two X chromosomes, while most men have one X and one Y chromosome. For women, one of the X chromosomes is mainly switched off, and the one that remains active seems to be chosen at random during the first few weeks of pregnancy. So half of a woman's cells generally use the X chromosome inherited from her mother, and the other half the one from her father. If one X has a harmful mutation, cells that use the other X can compensate. This explains why it is rare for women to be colour-blind, while around 8% of men cannot see a difference between red and green, and some are totally colour-blind. Almost all women can see 1m colours, but 5-15% of women have a visual superpower and are able to see 100m colours.

(Men are genetically programmed to have greater muscle power, lift heavier weights and run faster. More female embryos are lost during the early stages of pregnancy but are more likely to survive birth and onwards; more males die at and soon after birth.)

The two X populations cooperate and share not just genetic material with one another but also proteins and enzymes, which give an extra ability to handle disease. Even in tissues where the ratio of the Xs is 50:50, that can change. With a skin injury, one population of X cells might take over the healing process, but the ratio will drop back to 50:50 once healing is complete. If the heart cells carrying paternal X survive the lack of oxygen, it will be that population that survives; that benefit can occur in other organs such as the liver and kidneys.

The X chromosome is rich in immune-related genes. This means that women's bodies can cell population shift to the more effective X for an illness. One important group of genes on X helps cells recognise single-stranded RNA viruses,such as the coronavirus. Woman therefore have twice the options of recognising such a virus. The gene for the ACE2 protein is also on the X.

A further advantage for women is that the male hormone testosterone supresses the immune system, while the female hormone oestrogen makes it more aggressive. Although after the menopause, oestrogen levels decline, female cells still tend to be more critical and powerful in defending against a possible attack.

The downside to XX is that women have higher rates of autoimmune conditions. Female hormones (oestrogens) stimulate the immune system, while male testosterone inhibits it, but even before puberty, autoimmunity is still higher in females. 

In both sexes, in the fetus, the thyroid gland immune cells go through an "educational process"; if immune cells recognise other cells from the person's body, the immune cells self-destruct. This happens so that once the baby is born, autoimmunity does not happen. This works well in males, but in females, who have two genetically different cell populations, it is more likely that not all self-recognising cells are destroyed.

On the other hand, having a somewhat autoreactive immune system means XX can more easily detect microbes that resemble human cells. It may also explain why XX have a lower chance of certain cancers; women may be clearing pre-malignant cells before they are detectable medically. This pattern seems to hold true even with cancers that start before puberty, although higher rates of smoking and drinking in males does have an effect.

This sex difference is increasingly recognised but public and health professionals alike are accustomed to attributing the differences to behavioural issues. And it is difficult to understand the difference between biological strength and physical strength, and that a five-foot-three woman has a survival advantage over a six-foot male Olympic weight-lifter. There are also implications for treatments as women (i.e. XX) have different sensitivity to medications.

Moalem believes that having two versions of X explains why women are less vulnerable to certain congenital disorders and better at fighting off infections, including the coronavirus.

• Supercentenarians (over 110) are 95% female.
• More girls than boys reach their first birthday.
• Girls who have asphixia at birth do better cognitively than boys.
• In general, drugs are metabolised slower by XX, and gut transit time is slower, so XX have to wait longer after eating to have an empty stomach.
• Melanoma kills twice as many young men as women, because XX benefit from stronger immune response and female sex hormones, while XY are not necessarily using less sun screen or not going to their doctor. 

Source: The stronger sex by Sharon Moalem, in New Scientist, 1 August 2020.
Source: Feature in Good Housekeeping, August 2020.

British Postcodes

Mail Obsession: a journey round Britain by postcode by Mark Mason. A history of the British postcode system and some facts about each of the postcode districts.

The first attempt at using postcodes was a scheme for London set up by Sir Rowland Hill in 1857. He split the capital into N, NE, E, SE, S, SW, W and NW plus EC (East Central) and WC (West Central). Later Anthony Trollope merged NE with E, and splitting S between SW and SE, leaving just eight codes. The 1930s saw postcodes introduced in larger towns and cities but the current system was introduced starting with Croydon.

There are 124 UK postcode areas, including the Crown Dependencies of Jersey, Guernsey and the Isle of Man. Postcode areas, towns and districts do not follow political boundaries and usually serve larger areas than the place names indicate.

The postcode area is the largest geographical unit and forms the initial one or two characters of the alphanumeric code, which are generally intended as a mnemonic, e.g. AB for Aberdeen. Areas are divided into districts with a number, with number 1 always used for the main sorting office. As a general rule, large post towns are are numbered from the centre out, with outlying districts having higher numbers. The area and district is followed by a space. Then there is a number to indicate sectors within districts, e.g. AB10 1. The following two letters identify streets or sides of a street, e.g. AB10 1FQ which is the postcode for Aberdeen Art Gallery in Schoolhill.

Area: SP = Salisbury Plain. Districts: SP1 (main sorting office), SP2, SP3, SP4 and SP5 are used for Salisbury. SP6 = Fordingbridge # SP7 = Shaftesbury # SP8 = Gillingham # SP9 = Tidworth # SP10 and SP11 = Andover.

Zeroes are high rather than low, so only used after numbers 1 to 9 have been used. The final two letters in a postcode are never CIKMOV.

Did you know?

• Some postcodes cross national boundaries. 
• People can't get new build house insurance cover until a postcode is allocated.
• SE2 residents of Bexley Heath get charged London levels of insurance premiums.
• Because Kirkwall (KW) includes Orkney, mainland residents of this postcode end up paying higher delivery charges which are applied to the all KW addresses.

Only four non-London areas have single letter codes: S is Sheffield, B is Birmingham, G is Glasgow, L is Liverpool and M is Manchester.

The full list of postcodes areas.
AB = Aberdeen # AL = St Albans # B = Birmingham # BA = Bath # BB = Blackburn # BD = Bradford # BH = Bournemouth # BL = Bolton # BN = Brighton # BR = Bromley # BS = Bristol # BT = Belfast # CA = Carlisle # CB = Cambridge # CF = Cardiff # CH = Chester # CM = Chelmsford # CO = Colchester # CR = Croydon # CT = Canterbury # CV = Coventry # CW = Crewe # DA = Dartford # DD = Dundee # DE = Derby # DG = Dumfries and Galloway # DH = Durham # DL = Darlington # DN = Doncaster # DT = Dorchester # DY = Dudley # E = London East # EC = London East Central # EH = Edinburgh # EN = Enfield # EX = Exeter # FK = Falkirk # FY = Blackpool / Fylde (Bolton already using BL) # G = Glasgow # GL = Gloucester # GU = Guildford # GY = Guernsey # HA = Harrow # HD = Huddersfield # HG = Harrogate # HP = Hemel Hempstead # HR = Hereford # HS = Outer Hebrides # HU = Hull # HX = Halifax # IG = Ilford # IM = Isle of Man # IP = Ipswich # IV = Inverness # JE = Jersey # KA = Kilmarnock (Kilmarnock and Ayr?) # KT = Kingston-upon-Thames # KW = Kirkwall # KY = Kirkcaldy #  L = Liverpool # LA = Lancaster # LD = Llandrindod Wells # LE = Leicester # LL = Llandudno # LN = Lincoln # LS = Leeds # LU = Luton # M = Manchester #  ME Rochester (Medway towns) #  MK = Milton Keynes # ML = Motherwell # N = London North # NE = Newcastle # NG = Nottingham # NN = Northampton # NP = Newport # NR = Norwich # NW = London North West # OL = Oldham # OX = Oxford # PA = Paisley # PE = Peterborough # PH = Perth # PL = Plymouth # PO = Portsmouth # PR = Preston # RG = Reading # RH = Redhill # RM = Romford # S = Sheffield # SA = Swansea # SE = London South East # SG = Stevenage # SK = Stockport # SL = Slough # SN = Swindon # SO = Southampton # SP = Salisbury Plain # SR = Sunderland # SS = Southend-on-Sea # ST = Stoke-on-Trent # SU = Sutton (Sutton and Morden?) # SW = London South West # SY = Shrewsbury # TA = Taunton # TD = Galashiels # TF = Telford # TN = Tonbridge # TQ = Torquay # TR = Truro # TS = Cleveland # TW = Twickenham # UB = Southall (Uxbridge) # W = London West # WA = Warrington # WC = London West Central # WD = Watford # WF = Wakefield # WN = Wigan # WR = Worcester # WS = Walsall # WV = Wolverhampton # YO = York # ZE = Lerwick (Zetland) #

Also
BF = British Forces  #  XX = used by online retailers for returns by Royal Mail.

The British Postal Museum and Archive is at 15-20 Phoenix Place, London, WC1X 0DA.

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